This invention relates generally to centrifuges and more particularly to centrifuges for effecting the continuous separation of insoluble liquids having different specific gravities.
Centrifuges have been used for many years to remove insoluble contaminants from a liquid. For example centrifuges have been used for separating a lighter phase liquid, e.g., oil, from a heavier phase liquid, e.g., water. Such centrifuges typically include a housing in which a rotary basket or bowl is disposed. The contaminated liquid, e.g., the mixture of liquids to be separated, is introduced into the bowl (typically through a opening in the top wall of the bowl). The bowl is rotated or spun about a vertical axis at a high rate of speed to cause the liquids to accelerate and separate, with the heavier phase (i.e., higher specific gravity) material being displaced into an annular volume located on the sidewall of the centrifuge bowl and the lighter phase material being displaced into another annular volume located on top of ("floating") on the heavier phase liquid. A respective outlet or "escapement" is provided in communication with each liquid volume to enable that liquid to be withdrawn from the bowl, while the contaminated liquid, i.e., the mixture of the two different phase liquids is introduced therein. For example, in one common type of centrifuge the bowl or basket utilizes a conical separator plate to establish the two annular volumes, with the escapements for those volumes being located closely adjacent the rotation axis. In another type of centrifuge no conical separation plate is used, but the outlets or escapements for the two liquids are still located closely adjacent the rotation axis. Both of these types of prior art centrifuges are somewhat complex in construction and of limited utility.
Clinton Centrifuge, Inc. of Hatboro, Pa. markets a centrifuge under the trademark CLINTON LIQUID-LIQUID SEPARATOR for accomplishing the reclamation of a lighter phase liquid from a higher phase liquid which is simpler in construction than many other types of prior art centrifuges. Moreover the CLINTON LIQUID-LIQUID centrifuge effects the removal of the two liquids from positions radially remote from the rotation axis to expedite the separation procedure by taking advantage of the increased centrifugal forces extant at the radially remote positions. In particular the CLINTON LIQUID-LIQUID centrifuge includes a housing having a basket therein which is rotated or spun about a vertical axis at a high rate of speed to cause the liquids to accelerate and separate, with the heavier phase liquid being displaced into a cylindrical annular volume located on the sidewall of the centrifuge bowl and with the lighter phase material being displaced into another annular cylindrical volume floating on the heavier phase liquid. A sharp edged "skimmer" tube is mounted in the housing to extend into the lighter phase liquid volume in the bowl to cause that liquid to be intermittently discharged under pressure into the skimmer. In particular the skimmer tube extends through a central opening in the top wall of the bowl radially remote from the rotation axis and includes a razor edged radially outwardly extending portion arranged to be adjustably positioned in the annular volume of the lighter phase material to skim it off. The skimmer tube is coupled to a conduit in the housing through which the reclaimed lighter phase liquid flows to an outlet for coupling to external means for collecting that liquid. A horizontally disposed ring is located within the centrifuge basket spaced inwardly from the basket's sidewall and below its top wall to form an annular passageway through which the heavy phase liquid may flow for ultimate gravity discharge. To that end the heavy phase liquid which exits that annular passageway flows around the inner lip of the top wall of the basket and over it to a chamber located within the housing below the basket. That chamber includes an outlet arranged to be coupled to means for collecting the heavy phase liquid.
While the CLINTON LIQUID-LIQUID SEPARATOR centrifuge is suitable for its intended purposes and is somewhat simpler in construction than many other prior art liquid separation centrifuges, it never the less still leaves something to be desired from the standpoint of effectiveness and efficiency of operation.